Guideway switch apparatus for magnetically levitated vehicles

ABSTRACT

A switch is used, at the divergent zone, to cause the vehicle bogie to follow one path or the other in the guideway. This is accomplished by substituting an attracting magnetic array on the side that the vehicle bogie is desired to follow. The switch may operate without moving parts, so there is no inertial penalty to limit operational frequency. The switch is designed to fail gracefully in the absence of activation power or control signals. Further, the switch is designed to ensure that there would be no derailment or dropping of a vehicle.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims benefit to U.S. Provisional PatentApplication No. 60/870,884, filed Dec. 20, 2006, the complete disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention is directed to transportation or transit systems,and more specifically, to networked guideway transit systems designed toenable the movement of large numbers of passengers or parcels in aflexible manner.

Guideway-based transportation systems have been used to transport peopleor goods. One example is a “Personal Rapid Transit” (PRT) system. In thePRT system, each vehicle carries just one party or small group (orpayload) from their origin directly to their destination, starting at atime determined by the party's arrival at its origin. Vehicles aretypically piloted by computer and move non-stop along guideways withdiverging and merging paths. At origin and destination access points(termed “portals”) vehicles stop on separate siding guideways so they donot impede the progress of other vehicles that are continuing to otherdestinations.

However, the use of wheels as the primary method of suspending vehiclescontinues to pose a significant barrier to PRT implementation. Inaddition, the unavoidable wear accompanying wheels rolling on tracksbecomes a significant maintenance problem when a typical system mightutilize thousands, or tens of thousands of vehicles. Further, the use ofwheels imposes a speed limitation on the vehicles. Small, cheap wheelsare generally not capable of even the speed range over which automobilesoperate. Wheels capable of that range of speed or higher becomeexpensive and heavy, and their potential failure becomes a serioussafety issue. Thus, current PRT systems lack an economical, reliable andlightweight means to carry vehicles in slower speed, tight systems andfaster, longer distance systems.

Further, in a PRT system, a switch, that is the piece of guideway thatmakes possible the splitting or merging of paths, may be one of the mostimportant and valuable technological features. However, it iscomplicated and costly to construct switches that change the directionsof vehicles traveling at any operational speed for the portion ofnetwork in which it is located. In some PRT systems, underhangingvehicles are desirable. However, the risk of a vehicle becoming detachedand actually falling out of the guideway is an inherent problem ofswitches conventionally designed for underhanging vehicles. Thus, it isneeded to construct switches that prevent the derailment, jamming orfalling out of a vehicle under any conditions or circumstances.

BRIEF SUMMARY

The present invention is directed to a method and system for providing aswitch that directs moving vehicles to a desired path on guideways of anetworked guideway transit system. The networked guideway transit systemcombines permanent magnet levitation with electrodynamic stabilizationand linear motor propulsion. That is, the networked guideway transitsystem uses the permanent magnets to provide primary lift and useselectrodynamic repulsion to create centering forces at most operationalspeeds while integrating linear motor functions with the electrodynamiccentering function. The switch is used, at a divergent zone, to cause avehicle bogie that couples a vehicle to the guideway to follow one sideor the other of the diverging guideway magnet components. This isaccomplished by use of an attracting magnetic array on the side that thevehicle bogie is desired to follow.

In some embodiments of the present invention, a switch apparatus isprovided to direct a vehicle bogie in a networked guideway transitsystem to a desired path at a divergent portion of a guideway. Theswitch apparatus comprises an electromagnet component for attracting oneside of a vehicle bogie in order to direct the vehicle bogie to aparticular direction in the guideway. The switch apparatus alsocomprises a guideway levitation component for lifting the vehicleattached to the vehicle bogie and an electrodynamic repulsion componentfor passively centering the vehicle bogie.

In another embodiment of the present invention, a networked guidewaytransit system that utilizes permanent magnets levitation andelectrodynamic repulsion is provided. The networked guideway transitsystem includes a vehicle bogie that comprises a set of bogie segments,each of which includes a bogie levitation component for providinglifting forces and a bogie propulsion component for providing propulsionforces on the vehicle bogie. The vehicle bogie supports a vehicle in thenetworked guideway transit system. The networked guideway transit systemincludes a guideway that comprises a first portion and a second portion,each portion including a set of modular guideway blocks. Each modularguideway block in the first portion includes a guideway levitationcomponent for lifting the vehicle, a guideway propulsion component, anda electrodynamic repulsion component for passively centering the vehiclebogie. Each modular guideway block in the second portion includes anelectromagnet component for directing the vehicle bogie, a guidewaylevitation component for lifting the vehicle and an electrodynamicrepulsion component for passively centering the vehicle bogie.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1A is a perspective view of a networked guideway system inaccordance with an embodiment of the present invention;

FIG. 1B is a perspective view of the networked guideway system showingan exposed view of modular guideway blocks of the guideway in accordancewith an embodiment of the present invention;

FIGS. 2A and 2B are cross-sectional views of an exemplary embodiment ofa bogie segment used in the networked guideway system;

FIGS. 3A and 3B are perspective views of the networked guideway systemof FIG. 1A showing an exposed view of bogie segments of the vehiclebogie in accordance with an embodiment of the present invention;

FIGS. 4A and 4B are cross-sectional views of an exemplary embodiment ofthe modular guideway block used in the networked guideway system;

FIG. 5 depicts a cross sectional view of an exemplary embodiment of aportion of guideway showing a bogie segment nested in a modular blockguideway;

FIG. 6 depicts an exemplary way of implementing the EDR centeringsubsystem in the networked guideway system; and

FIGS. 7A-7F are cross-sectional views of different embodiments of thebogie segment and the modular guideway block used in the networkedguideway system;

FIGS. 8A-8C are cross-sectional views of a switch portion of theguideway in accordance with an embodiment of the present invention; and

FIGS. 9A-9C are cross-sectional views of a switch portion of theguideway in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following detailed description describes exemplary embodiments ofthe present invention. Although specific system configurations and flowdiagrams are illustrated, it should be understood that the examplesprovided are not exhaustive and do not limit the present invention tothe precise forms and embodiments disclosed. It will be apparent to oneskilled in the art that the invention may be practiced without some orall of these specific details. In other instances, well-known processsteps have not been described in detail in order not to unnecessarilyobscure the invention.

A method and system to integrate magnetic levitation technologies withina networked guideway transit system is provided. The magnetic levitationis used to replace wheels as the primary means of vehicle suspension andthus the automated transit systems (e.g., PRT system) can be madecommercially and economically feasible. More specifically, a method andsystem use permanent magnet repulsion with induction-based repulsionwithin the networked guideway transport system, which can levitatepassively with motion.

Generally, the guideway in the networked guideway transit systemincludes a point where the guideway begins to split into two separateguideways, i.e. a divergent zone, the two sides of the guideway arespaced progressively farther apart. A switch is used, at the divergentzone, to cause the vehicle bogie to follow one side or the other of thediverging guideway. The switch may use electromagnet sources instead ofpermanent magnets so that the magnetic force can be altered to directthe vehicle bogie to either path. The switch can use any suitablemagnetic sources as long as the magnetic force of the magnetic sourcescan be altered to direct the vehicle bogie to either path. The switchmay operate without moving parts, so there is almost no inertia penaltyto limit operational frequency. The switch is designed to failgracefully in the absence of activation power or control signals.Further, the switch is designed to ensure that there would be noderailment or dropping of a vehicle. That is, vertically attractingmagnets or electromagnets are used to deflect segments of an articulatedvehicle bogie without causing loss of suspension stability orrequirement of any moving parts or active position control subsystems.The switch operates at very high vehicle speeds and switchingfrequencies, i.e., short vehicle headways.

Magnetic Levitation

Magnetic levitation (hereinafter, “Maglev”) may provide advantagescompared to traditional wheels on tracks. Generally, Maglev has low orzero mechanical friction and thus parts in a Maglev system do not wearfrom contact. It has a wide range of speeds over which it can operateand in operation it generates relatively low noise levels.Conventionally, Maglev as applied to traditional large train systemarchitecture provides only marginally improved service characteristics,i.e. primarily shorter transit times on long runs where extreme groundspeeds are attainable and practical. Because aerodynamic losses prevailat high speeds and powerful propulsion systems are required to overcomethese losses, the extreme ground speeds achievable with Maglev are onlyfeasible with large trains and large footprint guideways, and areobtained at an enormous energy cost. And with existing complex Maglevsystems that require sensors, positional feedback, active control, oreven active levitation power, this marginal benefit comes at much highercost in basic infrastructure, and at increased risk for technical oroperational problems.

In general, the combination of functional capabilities of Maglevtechnology and PRT systems may have been considered counterintuitive.The counterintuitive nature of this relationship is due to the failureof recognizing the performance potential of the respective technologies.In contrast, in forgoing described and supplied embodiments, using aproper form of Maglev technology to replace wheels as the primary meansof vehicle suspension makes a networked guideway transit system bothfeasible and commercially achievable as a method of moving vehicles. Inaddition, linear motor propulsion used with the Maglev suspension allowsthe great majority of the guideway to have no contact and littlemechanical friction. This means less wear and less dust is generatedcompared to conventional Maglev systems, both of which factorscontribute to lowering maintenance and improving reliability.

Guideway Transit System

As will be discussed in greater detail below, a networked guidewaytransit system 100 includes levitation, centering and propulsioncomponents, utilizing permanent magnets to provide primary levitationand electrodynamic repulsion to create centering forces.

With reference to FIGS. 1A and 1B, perspective views of a networkedguideway transport system 100 are depicted in accordance with someembodiment of the present invention. The networked guideway transitsystem 100 generally includes a guideway 120 and a mating vehicle 160.The guideway 120 has a suitable geometry to support and guide thevehicle 160 at any speed reasonably associated with such a networkedguideway transit system. The guideway 120 may include several modularguideway blocks that are straight and short segments of the guideway. Asused herein, the modular guideway block refers to a basic unit of theguideway. As depicted in FIG. 1B, the modular guideway blocks may beloaded into a shell that forms the guideway structural beam 122 to carrythe load between support columns 115.

In the networked guideway transit system 100, the vehicle 160 issupported by a vehicle bogie (not shown) that interlocks with theguideway 120. As will be discussed in detail below, the vehicle bogie isa guideway element that couples a vehicle to the guideway. The vehiclebogie used for the networked guideway transit system may include severalbogie segments, each of which includes levitation, centering andpropulsion components. Each bogie segment may have a finite length inorder to fit in a single modular guideway block 110. One non-limitingexample of the bogie segment is shown in FIGS. 2A and 2B.

It is noted that the figures described herein are not meant to show theexact or relative sizes, or the locations of the various components, butrather to illustrate the general configuration for the purposes of thediscussion.

FIGS. 2A and 2B illustrate cross sectional views of the bogie segment200 in accordance with an embodiment of the present invention. The bogiesegment 200 includes primary permanent magnet repulsion (PMR) arrays,such as a bogie lifting magnet unit 204, that provide upward forces onthe vehicle bogie. The bogie segment 200 further includes clampingmagnets, for example a bogie clamping magnet unit 206, that providedownward or vertical clamping forces on the bogie.

The clamping magnets of the bogie segment 200 are additional staticmagnetic field sources, generally high field permanent magnets withpoles aligned so as to be in repulsion to magnets on the guideway. It isnoted that the clamping magnets are static magnets and can be located onthe guideway or the vehicle bogie. In the illustrated embodiment, thebogie clamping magnet unit 206 is located on the vehicle bogie and makesuse of the bottom sides of the guideway magnets to produce repulsion. Inthis embodiment, the bogie clamping magnet unit 206 may be used to add adownforce to the overall vertical force on the bogie segment 200. It isfurther noted that the bogie clamping magnet unit 206 may be sized andpositioned as appropriate such that the bogie clamping magnet unit 206does not significantly decrease the levitation height provided by thebogie lifting magnet unit 204, but in the event the vehicle bogie ridestoo high because of load perturbations, the bogie clamping magnet unit206 forces the bogie back down more rapidly than gravity alone. This maystiffen the suspension and assist to maintain the vertical position ofthe vehicle bogie. Also, in the case where an end of the vehicle bogieprotrudes into a section of the guideway that does not contain PMRcomponents for lifting, the bogie clamping magnet unit 206 may preventthe protruding end of the vehicle bogie tipping down into thatunsupported section by holding down the opposite end.

In addition, the bogie segment 200 can include a passive centeringdevice (e.g. a device including the electrodynamic repulsion (EDR)centering components 208) that comprises moving coils or conductorstacks. The EDR centering components 208 may primarily provide centeringforces but may also provide some propulsion forces to the bogie segment200. The bogie segment 110 may contain more PMR components (linearmagnetic arrays) for mating, such as a bogie propulsion magnet unit 202,each arranged to be in opposition to corresponding PMR components(linear magnetic arrays) in the guideway.

In one embodiment, the EDR centering components 208 may also function aspropulsion components. As will be discussed in greater detail below, thecoils in the conductor arrays (not shown) of the EDR centeringcomponents 208 are energized to provide forward thrust or regenerativebraking by interaction with the magnets arranged in the guideway. Theelectrical power may be delivered to the moving coil, the stationarycoil or a combination thereof. In some embodiments, both stationary andmoving coils are included in the vehicle bogie. In such embodiments, thestationary coils can deliver primary electrical power to the vehiclebogie, which is converted to the kinetic energy of motion, while themoving coils deliver secondary electrical power to the onboard energysupply by tapping into the same kinetic energy. In this manner, theelectrical power can be transmitted from the guideway to the vehiclebogie (eventually to the vehicle) without contact. The stationary coilsmay be combined into a modular guideway block. It is noted that thebogie segment described in conjunction with the aforementionedembodiments may include other components well known in thetransportation art but not shown for ease of illustration, such ascentering rollers, skids, electric motors that provide a drive source tothe vehicle, etc.

FIG. 3A depicts a perspective view 300 of the networked guideway transitsystem showing an exposed view of bogie segments. As shown, one vehiclebogie 360 may include a set of five bogie segments. In a preferredembodiment, the networked guideway transit system uses underhangingvehicles 160 to facilitate high-speed operation. The vehicle bogie 360is mounted on vehicle attachment fin 362 that attaches the underhangingvehicle 160 to the vehicle bogie. The vehicle bogie 360 is used forsupporting the underhanging vehicle 160 and for mating the underhangingvehicle 160 to the guideway 120. As described above, the lifting isgenerated by magnetic repulsion between permanent magnets of the PMRcomponents in the guideway modular block 110 and the vehicle bogie 360.FIG. 3B depicts another perspective view 300 of the networked guidewaytransit system showing an exposed view of articulated bogie segments.Each bogie segment has a size such that the bogie segment can be nestedin a modular guideway block 110. In order to navigate some portions ofthe guideway with tight radii, including diversion points of theguideway, the bogie segments of the vehicle bogie 360 may be articulatedto flex in a horizontal dimension. That is, the bogie segments of thevehicle bogie 360 may be hinged along its vertical front and rear edges.This arrangement may leave the vehicle bogie rigid in the pitch, orvertical dimension. Moreover, in this way, the full mass of the vehicle160 is distributed along the full length of the bogie segment. Inaddition, the bogie segments of the vehicle bogie 360 may be able totraverse sections of the guideway where there is not full magneticlevitation available.

In addition, it is possible to reduce the bogie size (the cross sectionof the bogie) by combining the motor propulsion and EDR centeringfunctions. The small cross section of the bogie reduces its aerodynamicresistance. Thus, its mass can be minimized. The largest lateraldimension may be kept small, which facilitates good track switch design.It should be noted that the roll stability of the bogie is not dependenton the lateral spread between the primary lifting PMR components, butrather is achieved by the vertical spread between the EDR centeringcomponents.

In one embodiment, several modular guideway blocks may be loaded into ashell that forms the guideway structure beam to carry the load. Theweight of the guideway beam is mostly static mass, not vehicle mass.Further, by using materials and methods designed to minimize the staticweight, cost and physical size of the guideway beam, the supportingstructure of the guideway (guideway beam) can be easily erected and themodular guideway blocks can be inserted with simple equipment. Further,the installation cost is minimized by the modular nature of the guidewaycomponents, which can be manufactured in a controlled factoryenvironment using mass production methods.

The modular guideway block of the networked guideway transit system willnow be described in more detail. In FIGS. 4A and 4B, cross sectionalviews of the modular guideway block are depicted in accordance with anembodiment of the present invention. FIG. 5 depicts a cut away view 500of a portion of guideway showing a bogie segment 360 nested in a modularguideway block 400 in accordance with an embodiment of the presentinvention.

The modular guideway block 400 also comprises several PMR componentsthat may be linear arrays of high field permanent magnets. Generally,there are two or more linear static magnetic arrays in the modularguideway block 400 as the PMR components. In one embodiment, the modularguideway block 400 includes a first PMR component, for example aguideway lifting magnet unit 420, that provides primary lifting andvertical clamping forces. As will be appreciated, the primary liftforces are produced by static magnets in the first PMR componentarranged in homopolar linear arrays, the long axis of the arrays alignedin the travel direction of the moving vehicle. The modular guidewayblock 400 further includes a second EDR component, for example aguideway propulsion magnet unit 430, that provides primary centeringforces and auxiliary propulsion forces. Permanent magnets used in theguideway lifting magnet unit 420 and the guideway propulsion magnet unit430 may vary in size depending on track locations.

The modular guideway block 400 further comprises EDR centeringcomponents, such as guideway propulsion coils 442, that passivelycenters a moving vehicle bogie. That is, the EDR centering components ofthe modular guideway block 400 and the EDR magnets of the bogie segment200 constitute an EDR centering subsystem that controls and centers themoving bogie via the interaction between the EDR magnets andelectrically conductive elements in the networked guideway transitsystem. There are various ways to implement the EDR centeringcomponents. For example, when the vehicle bogie is at standstill ormoving at low speeds (e.g., below a few meters per second), the EDRcentering components in the modular guideway blocks are not effective.In this case, centering rollers or skids (not shown) keep the vehiclebogie laterally centered. It is noted that the locations of the EDRmagnets and the EDR centering components of the EDR centering subsystemmay be exchanged so that various embodiments can include any suitablearrangements of the permanent magnets and coils. One non-limitingexample of implementing the EDR centering subsystem is depicted later inFIG. 6.

As discussed above, the PMR components and the EDR centering componentsincluded in the bogie segments and/or the guideway modular blocksperform well as a means of conveyance in the networked guidewaytransport system 100. That is, the levitation (lift force) produced bythe PMR components has good lift to magnet mass ratio, a significantlylow drag at all speeds and can ride over small gaps between adjacentsections. As such, the PMR components used in the bogie segments and themodular guideway blocks can be compact, much smaller than wheels of thesame carrying capacity and suspension stiffness. The PMR components haveno rotational inertia and lower mass than a comparable wheel system.

To control possible lateral instability in the PMR components and tomaintain the alignment of the lifting magnets (PMR components), one ormore EDR centering subsystems are used in the described embodiments. TheEDR centering subsystem comprises electrically conductive elements, forexample the guideway propulsion coils 442, that are in relative motionto the magnetic sources (e.g., propulsion magnet units). As the magneticflux varies within the conductors, electrical currents are induced toflow. The interaction of those currents with the magnetic fieldsproduces forces with drag and repulsion components. As discussed above,the EDR centering subsystem has the advantage of producing nearlyconstant force over a large range of transverse displacement. Thus, theEDR centering subsystem works well when displaced in a direction normalto the travel direction and the force direction. Also, the forceincreases as the separation between the magnets and conductorsdecreases, making the arrangement stable in that axis.

In one embodiment, the networked guideway transit system may utilize adual EDR arrangement that includes two magnetic arrays facing a set ofconductors, or conversely a set of linked conductor arrays bracketing amagnetic array. The restoring force may increase as the center elementmoves farther off the center plane in the dual EDR arrangements. Theseattributes make EDR centering subsystems complementary to thecharacteristics of the PMR components lifting arrangement in thenetworked guideway transit system.

As will be appreciated, there are a number of ways to implement EDRsubsystems in conjunction with the networked guideway transit system.One non-limiting exemplary way of implementing the EDR subsystem isdepicted in FIG. 6.

As shown in FIG. 6, the permanent magnet arrays (EDR magnets) in thebogie segment are located at the center with coils that are used aspassive centering device. The coils, such as guideway propulsion coils442, are connected in laterally opposite pairs in such a way that themotion induced voltages cancel when the magnet arrays are laterallyequidistant from the coils. In this embodiment, if the permanent magnetarrays are closer to one side than the other, current flows within eachcoil pair and the forces tends to push the magnets back to a centerposition. Both arrangements are present in embodiments discussed inconjunction with FIGS. 2A, 2B, 4A and 4B above. In the embodiments,electrical energy can be transmitted from the guideway to thebogie-vehicle or vice versa.

The degree of roll stability required on any particular section of theguideway is determined by several factors, including the curvature ofthe guideway, the speed of travel, the mass of the vehicle, and theposition of the vehicle, among others. Some of such factors can becontrolled for a particular period or position of the guideway magneticfields. For example, in a turn where the bogie-vehicle mass pushesagainst the outer wall of the guideway larger fixed magnets could beinstalled, while on the inner wall smaller magnets could be used. Inthis way, the centering force could be biased to anticipate andcompensate for required centripetal turning force. It is also possibleto drive the EDR coils, for example the propulsion coils 208, 442 (FIGS.2A, 4A), in such a way as to produce an active lateral force. Thisarrangement can be used in high-speed turns to reduce the magnetic dragincurred by the large passively induced currents that would otherwise bepresent. Generally, the energy required to actively drive the EDR coilsto produce lateral force is on the order of one fourth that required forproducing the same force by passive induction.

In an alternative embodiment, the networked guideway transit system mayinclude a series connection of multiple coils to increase inductance ofthe EDR centering subsystems, which tends to reduce overall centeringforce but also reduce magnetic drag and the velocity at which the dragforce transitions to centering force. This may be used for a lower speedsection of the guideway. Likewise, the series or parallel connection ofmultiple coil pairs to the electrical drive or sinking circuits affectsthe magnitude of the induced voltage and can be optimized for theexpected operational speed and power source characteristics.

Referring now to FIGS. 7A-7C, cross sectional views of exemplaryembodiments of a portion of guideway including a modular guideway blockand a bogie segment are depicted. As shown in FIG. 7A, an exemplaryembodiment 710 includes the EDR components that are shown as inwardlypointed permanent magnet arrays 430 in the guideway, outwardly focusedpermanent magnet arrays 202 on the bogie, and propulsion coils 442, 208.Motion in the travel direction induces voltages within the guidewaypropulsion coils 442 in the guideway and coils 208 on the vehicle bogie.In both cases, the coils are connected in laterally opposite pairs suchthat the motion-induced voltages within the coils tend to oppose whenthe vehicle bogie is on the center plane. This results in no currentflow within the coils.

When the vehicle bogie is biased toward one side of the guideway thevoltages increase in the coils on that side and decrease in the coils onthe opposite side. This results in a forward current in the coils on theclose side and a back current in the coils on the far side. The closeside experiences repulsion while the far side experiences attraction.This tends to bring the bogie back toward the center plane. The lack ofcurrents when the bogie is at the center plane results in very lowmagnetic drag at that position. Because there are laterally constrainingforces high and low, the bogie is resistant to rolling. The underhangingvehicle 160 (FIG. 3A) can be damped in its swinging motion with theresulting reaction forces taken up by the bogie and transmitted to theguideway without mechanical contact. Both the upper and lower centeringelements in this configuration can contribute to propulsion.

As shown in FIG. 7B, an exemplary embodiment 720 includes the PMRcomponents and the upper lateral centering elements similar to theexemplary embodiment 710 described above and a modified EDR subsystem.As with the exemplary embodiment 710, the upper lateral centeringelements may function as the primary motor in the exemplary embodiment720. The exemplary embodiment 720 may include lower centering elementshaving an EDR arrangement that uses a stack of planar conductiveelements 290 or a so-called ladder track instead of coils. The stack ofplanar conductive elements 290 is a passive electrical conductor array.The PMR components, such as guideway propulsion magnet unit 430, of theguideway are focused inward onto this conductor array. As the vehiclebogie moves, voltages are induced within the conductors. Because theguideway magnets, such as the guideway propulsion magnet unit 430, arearranged so that their lateral fluxes are oppositely directed there is asteep gradient in the lateral flux density with lateral position, withlateral flux density tending to zero at the center plane. The inducedvoltages are strongly dependent on the lateral flux components so atcenter plane minimum voltages occur.

As in the previous embodiment the voltages give rise to currents withinthe conductors and the interaction between these currents and componentsof the magnetic flux field tend to push the conductor stack (and thusthe bogie) back toward the center plane. Because there are laterallyconstraining forces high and low the bogie is resistant to rolling andthe underhanging vehicle 160 (FIG. 3A) can be damped in its swingingmotion. The resulting reaction forces taken up by the bogie may betransmitted to the guideway without mechanical contact. The advantagesthat the exemplary embodiment 720 has are simpler construction of theconductor array compared to the motor coils, and more powerful centeringforce for the same magnetic array size. In fact, the exemplaryembodiment 720 produces the strongest centering forces for a given sizeof centering element and it produces those strong centering forces nearthe pivot point where they are maximally effective at controllinglateral displacement of the vehicle.

As shown in FIG. 7C, an exemplary embodiment 730 includes severalpermanent magnet components and upper lateral centering elements in asimilar manner to the exemplary embodiment 710. The lower centeringelements in this embodiment 730 are also the same as the upper centeringelements, including the guideway propulsion coils 442 and a permanentmagnet component 202 for flux generation. This exemplary embodiment 730has the advantage of additional propulsion power from motor coils withguideway-sourced power. Also, significantly, this embodiment 730 usesmuch less magnet mass in the guideway, which may lead to substantialcost reductions in construction.

Referring now to FIGS. 7D-7F, more exemplary embodiments are depicted.As shown, bogie segments of these embodiments do not include clampingmagnets 206 (FIG. 2) for providing vertical clamping forces. Instead,the exemplary embodiments 740, 750, 760, include two EDR centeringsubsystems. The upper subsystem comprises a linear motor with bogiepropulsion magnet arrays 202, a guideway located drive module 449 andguideway propulsion coils 442. Motion in the travel direction inducesvoltages within the guideway propulsion coils 442. The coils areconnected in laterally opposite pairs such that the motion-inducedvoltages within the coils tend to oppose when the bogie is on the centerplane. This results in no current flow within the coils. When the bogieis biased toward one side of the guideway the voltages increase in thecoils on that side and decrease in the coils on the opposite side. Thisresults in a forward current in the coils on the close side and a backcurrent in the coils on the far side. The close side experiencesrepulsion while the far side experiences attraction. This tends to bringthe bogie back toward the center plane. The lack of currents when thebogie is at the center plane results in very low magnetic drag at thatposition.

The lower EDR centering subsystem comprises a pair of EDR components,such as guideway based planar conductor stacks 290 as shown. The samemagnets 202 that provide the flux for the motor and centering in theupper subsystem provide flux for the lower subsystem. In this case, themagnets are above the conductors but overlap by a small fraction of theconductor height. The transverse flux of the magnet arrays inducescurrents to flow within the guideway based planar conductor stacks 290.The magnitude of the currents varies with the flux density and with thedegree of overlap between the magnets and the conductors. When themagnets are closer to one side the flux density, and thus the inducedcurrent, is greater. When the overlap is greater the induced current isalso greater. The pattern of conductive pathways within the stacks issuch that the induced currents flow through vertically oriented pathsand are concentrated in the upper and lower edges of the stacks. Theinteraction of the longitudinal components of the magnetic fields andthe electrical currents through the vertical conductors causes forcesthat tend to push the conductors away from the magnets. Since themagnitude of the force is dependent on the magnitude of the electricalcurrents, the closer the magnets are to the conductors the larger therepulsion force between them. The electrical currents are dependent onthe proximity between the magnets and the conductors, and on themagnitude of the flux density at the conductor (which also increaseswith decreasing distance). Thus, this may produce a laterally stablearrangement.

The interaction of the transverse components of the magnetic fields andthe concentrated currents in the upper edges of the conductor stackscreate forces that tend to resist the vertical overlap of magnets andconductors, in effect pushing the magnets back up out of the spacebetween the conductor stacks. In the described embodiments, the liftgenerated by the motion of the bogie reduces or eliminates therequirement for the direct magnetic repulsion from the homopolarpermanent magnet arrays.

Switch for the Networked Guideway System

Generally, the guideway 120 in the networked guideway transit system 100includes a divergent zone where the two sides of the guideway are spacedprogressively farther apart. As described above, a switch is used, atthe divergent zone, to cause the vehicle bogie to follow one side or theother of the diverging guideway.

In some embodiments, the switch (the switch zones of the guideway) mayinclude electromagnets so that the magnetic force can be altered todirect the vehicle bogie to either path. In such embodiments, even inthe event that no power was supplied to the system and theelectromagnets failed to energize, the dead zone would be significantlyshort and would not cause a complete loss of lift. Instead, the vehiclebogie would travels this section with four of five segments in full PMRlevitation, but without benefit of the lateral guidance provided by theelectromagnetic arrays. Without the active electromagnets, the path ofthe vehicle bogie would be determined by the passive EDR centeringcomponents and inertia.

In an exemplary embodiment, a new electromagnet array may be added inthe switch, located above the bogie lifting magnet unit (primary PMRcomponent for lifting.) The two vertically opposite attracting guidewayarrays exert lateral forces that combine in the same direction and actto bring the PMR components in the vehicle bogie on the first side intoproper vertical alignment.

It is noted that the vehicle bogie is not pushed to the outer wall ofthe guideway but rather to a position where the PMR components in thevehicle bogie and the electromagnet array (in the switch) in anattraction mode are vertically aligned. As a result, the switch causesone side of the bogie to tend to follow the side of the guideway withthe dual attraction arrangement. In such cases, another side (secondside) of the vehicle bogie is still experiencing lift and lateral forcesthat push the vehicle bogie off from the center. The switch alsoincludes a electromagnet array operated in a repulsion mode, whichallows the second side of the vehicle bogie to experience a verticalclamping and a lateral push, at least while the vehicle bogie and theelectromagnet array are in proximity. However, as the sides of theguideway diverge and the guideway arrays are spaced farther apart, theleading edge of the vehicle bogie tracks one side with the electromagnetarray operated in the attraction mode and moves away from the other sidewith the electromagnet array operated in the repulsion mode. At somepoint the divergence becomes large enough that there is space enough fortwo complete sets of guideway magnet arrays. At this point, theorientation of all magnets in the modular guideway block is returned toa repulsion mode.

The switch will now be described in more detail in conjunction withFIGS. 8A-8C showing cross sections of a switch portion of the guidewayin accordance with an embodiment of the present invention. In FIGS.8A-8C, each cross section view depicts a portion of the guideway atthree different points 810, 820, 830 during a switching operation, forexample, a switch portion 810 immediately before divergence, a switchportion 820 during divergence and a switch portion 830 immediately afterdivergence.

As shown, in the first switch portion 810, the bogie segment islaterally trapped by upper centering/propulsion elements 420, 202 andlower centering/propulsion elements 430, 208. The lift is still providedby guideway permanent magnet arrays 420 at both sides acting on bogiemagnet arrays 204. Propulsion, if it is active, is provided by the upperand lower centering/propulsion elements.

In the second switch portion 820, the bogie segment is transiting aportion of the guideway 120 where the outer walls of the guideway havediverged, leaving a wider than normal space in the interior. Thepermanent magnet lifting arrays in the guideway are replaced withvertically polarized track switching homopolar electromagnetic arrays725, 726 within this portion. The electromagnetic arrays 725, 726 withinthis portion are energized by power sources within the guidewayelectronics module 449 in either of two directions. That is, theelectromagnetic arrays of the two sides are energized with oppositepolarity. On a first side of the guideway, the electromagnetic arrays725 are energized with the same polarity as the polarity of the bogielift magnets 204 so that there is attraction between those elements,both vertical and lateral. Because there is attraction both upward anddownward from the upper and lower electromagnet arrays, the net verticalforce can be minimized. The lateral attraction forces are summed,creating a strong net lateral attraction for the bogie lift magnets.This tends to pull the attracted side of the bogie segment intoalignment with the electromagnet arrays on the first side.

In the second switch portion 820, on a second side of the guideway theelectromagnetic arrays 726 are energized with the opposite polarity asthe bogie permanent magnets 204. As a result, there is repulsion betweenthe electromagnets and PMR components on the bogie, for example thebogie lifting magnet unit (PMR component) 204, the bogie clamping magnetunit (PMR component) 204, etc. Such repulsion causes the bogie magnetsto be moved laterally out from between the electromagnetic arrays on thesecond side. The net result of the pulling in on the first side 725 andthe pushing out on the second side 726 is to cause the bogie segment totrack toward the side with the attracting electromagnet arrays. Sincethe polarity of the electromagnet arrays can be reversed by simplyreversing the electrical current through the electromagnets, thedirection of bogie movement can be switched by choosing the direction ofcurrent. It is noted that the force attracting the bogie segment forcesa vertical alignment of the bogie lifting magnet unit 204 with theactive guideway electromagnets. Also, throughout the transit, thelateral repulsion (EDR) elements are still active on the attraction sideof the guideway, further preventing a collision of the bogie segmentwith the wall of the modular guideway block. Preferably, there may beone bogie segment out of five within the divergent track section at anytime so the remaining bogie segments continue to provide lift andstability for the whole bogie. The short length of divergent track alsomakes it mechanically improbable for the bogie to dive downward throughthe bottom of the guideway.

As shown in the third switch portion 830, the bogie segment hastransited the divergent section of guideway and is engaged with a fullyfunctional modular guideway block of the typical construction. When thefront segment of the bogie has transited the divergent section the bogieis well captured at both ends and is very stable. The guideway hasbecome two separate fully functional guideways free to follow divergentpaths.

Referring now to FIGS. 9A-9C, cross sections of a switch portion of theguideway including a bogie segment nested in a modular block aredepicted in accordance with another embodiment of the present invention.In the first switch portion 910, the bogie segment is still laterallytrapped by upper centering/propulsion elements 420, 202 and lowercentering/propulsion elements 430, 208. The lift is still provided byPMR components, such as the guideway lifting magnet unit 420 at bothsides acting on the PMR components, such as the bogie lifting magnetunit 204, in the bogie segment.

In the second switch portion 920, the bogie segment is transiting aportion of guideway 120 where the outer walls of the guideway havediverged, leaving a wider than normal space in the interior of theguideway. As discussed above, the guideway lifting magnet units in theguideway are replaced with vertically polarized track switchinghomopolar electromagnetic arrays 725, 726 within this portion. Theseelectromagnet arrays are energized by power sources within the guidewayelectronics module 449 in either of two directions. The electromagneticarrays of the two sides are energized with opposite polarity. If oneside of the electromagnetic arrays 725 is energized with the samepolarity as the polarity of the bogie lift magnets 204 then it providesattraction toward both the primary bogie lift magnets 204 and the bogieclamping magnets 206. Such attraction is both vertical and lateral.Because there is attraction both upward and downward from the upper andlower electromagnet arrays the net vertical force is minimized. But thelateral attraction forces are summed creating a strong net lateralattraction for the onboard lift magnets and onboard clamping magnets.This tends to pull the attracted side of the bogie segment intoalignment with the electromagnet arrays on that side. If the other sideof electromagnetic arrays 726 is energized with the opposite polarity asthe polarity of the bogie lift magnets 204 then it provides repulsiontoward both the primary bogie lift magnets 204 and the bogie clampingmagnets 206. This repulsion causes the bogie segment to be movedlaterally out from between the electromagnetic arrays on that side. Theresult of the pulling in (attraction) on one side 725 and the pushingout (repulsion) on the other side 726 is to cause the bogie segment totrack toward the side with the attracting electromagnet arrays.

As shown in the third switch portion 930, the bogie segment hastransited the divergent zone of the guideway and while exiting thedivergent zone, the bogie segment is engaged with a modular guidewayblock 932 of the desired path. When the front segment of the bogie hastransited the divergent zone, the bogie is well captured at both endsand is very stable.

A failsafe behavior of the switch and the networked guideway system willbe discussed in greater detail below. In case when the switch is asymmetric divergent zone, with each side curving away at the same rateand at laterally adjacent locations, then the electromagnets there wouldbe energized to direct a vehicle bogie to either curve. If an asymmetricdivergent zone is used where one side continues straight ahead while theother curves away, then energizing the electromagnets is only requiredin order to follow the curving side. Thus, even if a power or controlfails, a vehicle bogie entering this divergent zone would continue tofollow the straight path, which would then be the default path (theinertial path).

At the location where the full divergence is achieved and the singleguideway becomes two guideways, the exiting path, which was straightuntil that point, bends away but with full support of lifting andcentering components. The continuation path also has full lifting andcentering components beyond the point of full divergence. In thisarrangement, there is only one place where magnetic lateral pull isrequired, i.e., at the start of the continuation path. In otherlocations the vehicle bogie is guided by passive repulsion forces andinertia or, in the case of very low speed operation, auxiliary rollersor skids.

As discussed in detailed above, the network guideway system includes thepermanent magnet repulsion (PMR) components, consisting of static fieldmagnetic sources with poles arranged so that their fields oppose eachother and developing repulsion forces. Lateral accelerations of variousmagnitudes will be utilized on various parts of the network guidewaysystem as the vehicle bogie and the vehicle move through. It isadvantageous to execute the divergence in as short a travel distance aspossible in order to minimize the fraction of the vehicle bogie that isover the divergence at any time. The lateral acceleration on eachindividual bogie segment is a function of the radii of curvature of theguideway segment and the velocity of the bogie/vehicle.

It is contemplated that the spread between left and right levitationmagnets is minimized to reduce the required lateral separation. In oneembodiment, the separation is controlled to occur in a track lengthequivalent to one segment of the set of five bogie segments. In thisembodiment, the excessive lateral accelerations would allow theunderhanging vehicle to swing laterally. In such a position theunderhanging vehicle does not immediately experience the lateralaccelerations of the vehicle bogie but instead swings slightly toaccommodate the rapid movement of the vehicle bogie first one way thenback to centerline. It is important to note that the highest lateralaccelerations are imposed on only one segment of the vehicle bogie at atime, so the magnitude of the force required executing the maneuver ismuch reduced. Once the front bogie segment has traversed the divergentzone where it is engaged by one side only of the guideway, the behaviorof the electromagnets is less critical to the execution of theoperation. At the point where the leading edge of the vehicle bogie hasre-engaged a full complement of passive centering and levitationcomponents, the electromagnets could cease function and the operationwould still succeed, though at less than optimal performance. In fact,after the first moments of lateral acceleration on its leading edge avehicle bogie moving at speed will cross the divergent zone to re-engagethe full guideway beyond.

As discussed previously, the self-centering behavior of the attractivemagnet arrangements may preclude the need for lateral position sensingfor good operation under most circumstances. Note that in thecircumstance of extreme travel velocities (for example, upwards of 100mph (160 kph)) extreme lateral accelerations on the bogie segments mayrequire additional direct electromagnetic attraction during the initialcurvature. In that case, position sensing may be required to prevent thevehicle bogie from contacting the guideway wall.

The opposite operation of divergence is convergence, where two pathsmerge into one. This operation is accomplished by similar means,although in general it is more easily performed than the divergenceoperation. If the electromagnetic arrays of the switch are replaced withpermanent magnet arrays arranged to be in vertically attractingpositions and the whole configuration is turned around with respect tothe travel direction, then a vehicle bogie approaching this apparatuswill abruptly enter a zone where its front segment is magneticallycaptured by one side and the other is left hanging. As the two pathsconverge the front bogie segment will eventually ride over both sets ofattracting magnet arrays and be laterally captured between the usualpassive EDR centering components. At that point the magnet orientationsrevert to repulsion, the extra arrays are eliminated and the twoguideways have merged into one. It is noted that this configuration maybe implemented with no active components at all. As will be appreciated,it is important to keep the single sided track sections as short aspossible in the travel direction.

In a particular situation, a converging zone can act as a latch if onlyone side of its magnetic arrays is in attraction mode while the otherside is left in repulsion. As a vehicle bogie traverses this switch inthe convergence direction it will function much as the standardconvergence zone. But if a vehicle bogie traverses this configuration inreverse it will always follow one path, the path with the attractivemagnets. This type of switch may be useful in special situations, forinstance parking vehicles in holding bays alongside a low speed throughpath.

While illustrative embodiments have been illustrated and described, itwill be appreciated that various changes can be made therein withoutdeparting from the spirit and scope of the invention.

1. A switch apparatus for directing a vehicle bogie in the networkedguideway transit system at a divergent portion of a guideway, the switchcomprising: an electromagnet component for directing a vehicle bogie toa desired direction in the guideway; a guideway levitation component forlifting the vehicle attached to the vehicle bogie; and an electrodynamicrepulsion component for passively centering the vehicle bogie.
 2. Theswitch apparatus of claim 1, wherein the vehicle bogie is directed tothe desired direction by the polarity of the electromagnet component. 3.The switch apparatus of claim 2, wherein the polarity of theelectromagnet component is changed by reversing the electrical currentthrough the electromagnet component.
 4. The switch apparatus of claim 3,wherein the electromagnet component includes a first electromagnetarrays and second electromagnet arrays which are vertically polarizedhomopolar electromagnetic arrays.
 5. The switch apparatus of claim 4,wherein the first electromagnet arrays and second electromagnet arraysare arranged laterally opposite to each other.
 6. The switch apparatusof claim 4, wherein the first electromagnet arrays are energized in thedirection that attracts a permanent magnet component of the vehiclebogie.
 7. The switch apparatus of claim 6, wherein the secondelectromagnet arrays are energized in the direction that repels thepermanent magnet component of the vehicle bogie.
 8. The switch apparatusof claim 1, wherein the divergent portion is a portion of the guidewaywhere the guideway begins to split into two separate guideways.
 9. Anetworked guideway transit system that utilizes permanent magnetslevitation and electrodynamic repulsion, the networked guideway systemcomprising: a vehicle bogie that comprises a set of bogie segments, eachbogie segment including a bogie levitation component for providinglifting forces and a bogie propulsion component for providing propulsionforces on the vehicle bogie, wherein the vehicle bogie supports avehicle in the networked guideway transit system; and a guideway thatcomprises a first portion and a second portion, each portion including aset of modular guideway blocks, wherein each modular guideway block inthe first portion includes a guideway levitation component for liftingthe vehicle, a guideway propulsion component for moving the vehiclebogie, and a electrodynamic repulsion component for centering thevehicle bogie and each modular guideway block in the second portionincludes an electromagnet component for directing the vehicle bogie, aguideway levitation component for lifting the vehicle, and anelectrodynamic repulsion component for centering the vehicle bogie. 10.The system of claim 9, wherein the polarity of the electromagnetcomponent is reversed based on the desired direction of the vehiclebogie.
 11. The system of claim 10, wherein the polarity of theelectromagnet component is reversed by changing the electrical currentthrough the electromagnet component.
 12. The system of claim 9, whereinthe bogie levitation component includes a first permanent magnet forproviding forces for lifting the vehicle and a second permanent magnetfor providing forces for clamping the vehicle.
 13. The system of claim9, wherein the set of bogie segments is nested in the set of modularguideway blocks.
 14. The system of claim 9, wherein the second portionis a divergent portion of the guideway where the two sides of theguideway are spaced progressively apart.
 15. The system of claim 9,wherein the first portion is a non-divergent portion of the guideway.16. The system of claim 9, wherein the electrodynamic repulsioncomponent includes guideway propulsion coils and the bogie propulsionmagnet component is positioned at the center with the guidewaypropulsion coils.
 17. The system of claim 9, wherein the bogielevitation component includes a first permanent magnet component and asecond permanent magnet component placed in a linear arrangement, thefirst permanent magnet component providing forces for lifting thevehicle and a second permanent magnet providing forces for clamping thevehicle.
 18. A method for implementing a switch for directing a vehiclebogie in the networked guideway transit system at a divergent portion ofa guideway, wherein the switch comprises an electromagnet component fordirecting a vehicle bogie to a desired direction in the guideway, theelectromagnet component comprising a first electromagnet arrays andsecond electromagnet arrays, a guideway levitation component for liftingthe vehicle attached to the vehicle bogie and an electrodynamicrepulsion component for passively centering the vehicle bogie, themethod comprising: determining a desired direction for the vehiclebogie; determining the first electromagnet arrays that corresponds tothe desired direction; energizing the first electromagnet arrays in thedirection that attracts permanent magnet components of the vehiclebogie; and energizing the second electromagnet arrays in the directionthat repels the permanent magnet component of the vehicle bogie.
 19. Themethod of claim 18, wherein the first electromagnet arrays are energizedwith the same polarity as the permanent magnet components of the vehiclebogie while the second electromagnet arrays are energized with theopposite polarity as the permanent magnet components of the vehiclebogie.
 20. The method of claim 19, wherein the polarity of the firstelectromagnet arrays and the polarity of the second electromagnet arraysis changed by reversing the electrical current through the electromagnetcomponent.
 21. The method of claim 18, wherein the first electromagnetarrays and second electromagnet arrays are arranged in laterallyopposite to each other.
 22. A method for conveying a vehicle bogie alongeither of two guideway paths that converge to a single path within anetworked guideway transit system, wherein the guideways includeguideway levitation components for lifting the vehicle attached to thevehicle bogie, electrodynamic repulsion components for passivelycentering the vehicle bogie and electromagnet guidance components fordirecting a vehicle bogie along its incoming pathway until the twopathways merge to one, the electromagnet guidance components comprisingfirst electromagnet arrays and second electromagnet arrays, the methodcomprising: detecting the vehicle bogie approaching the convergentportion of a guideway; and energizing the first electromagnet arrays inthe direction that attracts the permanent magnet component of thevehicle bogie and energizing the second electromagnet arrays in thedirection that repels the permanent magnet component of the vehiclebogie.
 23. The method of claim 22, wherein the first electromagnetarrays and the second electromagnet arrays are replaced with permanentmagnet arrays with the same polarity as the permanent magnet componentsof the vehicle bogie.
 24. The method of claim 22, further comprising:detecting the vehicle bogie moving in a backward direction; determininga pathway for the vehicle bogie to follow; and energizing the firstelectromagnet arrays in the direction that attracts the permanent magnetcomponent of the vehicle bogie and energizing the second electromagnetarrays in the direction that repels the permanent magnet component ofthe vehicle bogie, wherein the first electromagnet arrays corresponds tothe intended guideway path.
 25. The method of claim 23, wherein thefirst permanent magnet array has the same polarity as the permanentmagnet components of the vehicle bogie and the second permanent magnetarray has the opposite polarity as the permanent magnet components ofthe vehicle bogie such that the vehicle bogie moving in the backwarddirection is to follow the determined pathway.